At Vandenberg Air Force Base in California this week, the IBEX spacecraft is undergoing testing of its science instruments. On Monday, Aug. 11, the spacecraft will be fueled. Meanwhile, the upper stage motor was spin-balanced on Aug. 7. This will be followed by spacecraft spin balancing on Aug. 14. On Aug. 15, IBEX will be mated to the upper stage, and the integrated stack spin-balanced the following day.

At the Orbital Sciences launch vehicle hangar, prelaunch processing of the Pegasus XL rocket continues on schedule. Mating of the second and third stages is under way. Mating of the first and second stages is scheduled for next week.

The L-1011 carrying the Pegasus XL rocket with IBEX is currently planned to depart from Vandenberg on Sept. 25. After a stop in Hawaii, the flight will continue and arrive at the Reagan Test Site at Kwajalein Atoll in the south Pacific on Sept. 26.